If you create written content - be it a book, a blog post, or documentation for an SDK - you will be aware that some outlets might have a formalised style guides (like this one by Google)
Others might not (like your personal blog), but that doesn't mean your personal blog wouldn't benefit from having a style guide!
Vale is a linter for prose. It doesn't teach you how to write (there are other tools for that), but it rather focuses on the style of your writing, and helps to ensure consistency across multiple authors (or even to be consistent with yourself).
Too learn more about how Vale can help you, check out Introducing Vale, an NLP-powered linter for prose by Joseph Kato.